Origin of the Universe -- High Energy Physics


Universe_Evolution_LBL

The above picture (by LBNL Particle Data Group) shows the evolution of the Universe with emphasis of the very early stage within the first 100 seconds. The evolution is given by a log-scale in time, showing that there were so many critical steps in early stages as early as < 1 nano second from the Big Bang. The Universe started from nothing (other than photons) with so-called Inflation. Then at around 0.1 nano second after the Big Bang, the first phase transition occurred at the Electro-Weak Scale, called Higgs Mechanism. As a result, particles were able to acquire their masses.

4problems

At around the same time, perhaps the invisible particle called dark matter was produced and came out of thermal equilibrium. This is the place where Arisaka's group has keen interests. What is dark matter? What is the mechanism of producing the dark matter? The figure above shows the evolution of the universe (going downwards in time), indicating today's biggest puzzles on the right side: The beginning, Inflation, dark matter and dark energy. Experimentally, dark matter is believed to be possible to detect in our labs, if nature is kind enough. At UCLA, together with other researchers, we have been trying to approach it using three complementary methods.


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